Tyres were a hot topic in the Sunday Times ingear motoring supplement this weekend. First there was a question about suitable tyres for travelling abroad during the winter and then the problem of tyres losing pressure was addressed.
JE Washington from Tyne and Wear posed this question to the Car Clinic: “Over recent months the front offside tyre of my 06-plate Jaguar XJ6 Sovereign has begun to lose about 3-4psi of pressure each week. My garage has tested the tyre for leaks to no avail. The other three tyres keep pressure perfectly, so could it be due to the alloy wheel?”
Dave Pollard, who has written several Haynes manuals and tested just about every car-related accessory out there, offered this advice: “All car tyres deflate gradually because rubber is naturally porous but a loss of 4psi a week suggests something more serious (4psi a month is too much). If the specialist is certain neither the tyre nore its valve is to blame, this suggests that the air is escaping from where the wheel meets the tyre. Ask your tyre specialist to check for any corrosion on the inside of the wheel that is preventing the tyre from fitting correctly. If found, this should be cleaned off with a wire brush and made smooth again.
“Alloy wheels themselves can sometimes become excessively porous, which will cause pressure loss. to confirm this diagnosis, swap the front tyres on the front wheels; if the problem moves, then it is due to tyre tyre. If it stays, then it is the fault of the wheel itself.
“Should you need a new wheel, it’s worth writing to your local Jaguar dealer asking for a goodwill contribution, especially if you used this firm for servicing. Another option is to check Jaguar owners’ clubs or vehicle dismantlers for a used wheel.
“Until this problem is resolved, you need to be diligent about checking the tyre pressure. Not only can this be dangerous, it could lead to uneven wear patterns or premature replacement.”
Denna Bowman, Head Office